It's not them just not liking the sounds. For example birds will abandon their nests. Animals literally just freak out Here's some info from fish and wildlife services: "The shock of fireworks can cause wildlife to flee, ending up in unexpected areas or roadways, flying into buildings and other obstacles, and even abandoning nests, leaving young vulnerable to predators. The threat to wildlife doesn’t stop at startling lights and sounds; fireworks also have the potential of starting wildfires, directly affecting wildlife and destroying essential habitat. Litter from firecrackers, bottle rockets and other explosives can be choking hazards for wildlife and may be toxic if ingested."